This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The purpose of this research is to study the sensitivity of young healthy adults and older healthy adults to a type of drug called cholinesterase inhibitors, such as pryridostigmine (Mestinon ), donepezil (Aricept ) and galantamine (Razadyne ). Some of these drugs are used to improve the memory function and behavior of patients with Alzheimer's Disease. Results from other studies suggest that some people may be more sensitive to the effects of these drugs than others;this research will be to determine if young adults may be more sensitive to the effects than older adults.